Machinists&#39; bench square



g- 16, 1955 G. T. HARRISON 2,715,278

MACHINISTS BENCH SQUARE Filed Jan. 6, 1955 19 FIG-61,13 11 0 I I I I /X I A" United States Patent 0 The present invention relates to bench squares, and

more particularly, to an improved bench square for use by tooimakers, machinists, andthe like.

A primary object of the present invention is to provide a bench square of an improved construction, which includes improved means for releasably securing a blade or straight edge in a base of improved form, whereby blades of different lengths or forms may be readily and simply interchanged with the base.

A further object is to provide such a bench square which is true and which maintains this trueness when blades are interchanged with the base.

Another object is to provide a bench square having a detachable blade, said square being simple to manufacture with an extremely high degree of accuracy, and being durable and easy to use.

Still another object is to provide a bench square hav ing detachable or interchangeable blades, the base for which provides greater support for the blades than has heretofore been attained in bench squares of this general And a further object is to provide a bench square of the detachable or interchangeable blade type which has an improved joint construction for connecting the blades to the base with a high degree of accuracy, whereby the blades will be perfectly disposed at a right angle to the bottom or supporting surface of the base.

Other objects and advantages of the invention will be hereinafter described or will become apparent to those skilled in the art, and the novel features thereof will be defined in the appended claims.

In the drawing:

Fig. 1 is a view in side elevation of a bench square embodying the present invention;

Fig. 2 is a view in elevation of the bench square of Fig. 1, looking towards the work piece-engaging face of the blade;

Fig. 3 is a top plan view of the bench square of Fig. 1;

Fig. 4 is a view in horizontal section, as taken on the line 44 of Fig. 1;

Fig. 5 is a view in vertical section, as taken on the line 55 of Fig. 3, showing only a portion of the blade in elevation;

Fig. 6 is a view in side elevation of the bench square with a modified blade; and

Fig. 7 is a top plan view of the bench square of Fig. 6.

Like reference characters designate corresponding parts in the several views of the drawing and in the following description.

Referring first to Figs. 1 through 5, the bench square includes a base or support 1 preferably of substantial mass. The base is preferably generally cylindrical in cross-section, and at the bottom thereof, it is provided with a radially outwardly projecting flange 2 which substantially enlarges the supporting area at the bottom of the base 1, while allowing the upper, cylindrical body of the base to be of a lesser diameter, with attendant reduction of the amount of material utilized and of the dead weight of the square as a whole.

To further reduce the weight of the square and to facilitate mounting the base on a rotatable arbor during manufacture, the base 1 is provided with an axially extended opening, as at 3. If the base be formed of solid stock, the opening 3 may be bored through the base, and if the base be cast or forged, the opening may be formed during the casting or forging operations. The base is readily mountable on a rotatable arbor by means of the opening 3, and the base may then be quickly and simply machined down and lapped to provide a smooth finish and true surface on the outer periphery thereof.

On one of its vertical sides, the base 1 is milled out to provide a vertical groove or slot 4 extending from the extreme upper end to the extreme bottom thereof. Extending radially into the slot 4 is a pair of openings 5, 5, and the base 1 is diametrically counter-bored to form recesses 6, 6 for the heads of a pair of socketed cap screws 7, 7, and this counter-bore also provides a pair of openings 8, 8 in axial alignment with the .openings 5, 5 to allow insertion of the screws 7, 7 into the openings 5, 5.

Adapted to be removably secured in the slot 4 by the screws 7, 7 is a blade 9 having an accurately ground sighting or knife edge it) formed by the beveled sides 11, 11 thereof. The beveled sides 11, 11 of the blade merge with hollow-ground, tapering walls 12, 12 which in turn merge with parallel side walls 13, 13. These parallel walls 13, 13 are accurately machined so as to snugly fit between the side walls of slot 4 in the base 1. The side of the blade 9 opposite the knife-edge 10 is provided with an accurately machined face 14 disposed in perfectly parallel relation to the knife edge 10 and in true right-angular relation to a supporting shoulder or stop 15.

The faces 14 and 15 of the blade and the faces of the slot 4, together with the top and bottom faces of the base 1, are so constructed and finished that the blade will always assume a true vertical position when it is assembled with the base. In this connection, the top and bottom faces of the base 1 are trued parallel to one another, and the base of the slot 4 which is defined by the face 16 is disposed at true right angles to the top and bottom faces of the base. In addition, the length 0 fhe blade from the shoulder 15 to the lower end of the blade is less than the length of the base. Therefore, the blade is positioned in a truly Vertical position by the vertical faces 14 and 16 of the blade and the base, and the shoulder 15 engaging the upper face of the base 1 locates the blade vertically so that the openings 5, 5 in the base are in axial alignment with screw-threaded openings 17, 17 in blade 9. Thus, when the screws 7, 7 are turned into the openings 17, 17, the blade 9 will be pulled into the slot 4 until the faces 14 and 16 of the blade and base are in firm abutting contact with each other, and accordingly, when the assembled square is placed upright on a machinists or tooimakers bench plate (not shown) which is provided with a truly plane surface, the knife edge 10 of the blade 9 will be disposed at a true right angle to the surface of the bench plate.

The screws 7, 7 are each preferably provided with a socketed head, and the openings 8 in the base allow the insertion of an Allen wrench into the socketed head for tightening the blade to the base.

This arrangement facilitates the attachment to and removal from the base of blades of various types and sizes. The blade 9 of Figs. 1 through 5 is a straight-edge type of blade which may also be used as a straight-edge when detached from the base 1.

In Figs. 6 and 7, there is shown a different type of blade from that of Figs. 1 through 5, but the base conare identical to that previously described, and therefore only the modified portion of the blade of Figs. 6 and 7 need be described further. The elements which are the same as those shown in Figs. 1 through are designated by primed reference characters, While the modified construction of the blade is designated by new reference characters.

The upper end of the blade 9 is provided with a horizontally disposed arm 18 having an extreme upper flat face 19 disposed at a true right angle to the knife edge This face 19 thus forms a square corner 20 with the knife edge 10 for checking inside angles of machined parts. In addition, the blade 9, when removed from the base 1', constitutes a square which may be used independently of the base 1 by placing the face 19 on the upper surface of a bench plate, with the knife edge 10 projecting upwardly, perpendicular to the bench plate.

In use, the square is placed on a bench plate or the bed plate of a milling machine, or other flat surface, with the blade 9 or 9 disposed vertically, and as it becomes necessary to lay out or check a work piece, the square is slid up against a face of the work piece. By sighting the knife edge 10 or 10' from a position at one side of the square, in its relation to the face of the work piece, any variation in the face of the work piece or appropriate lay-out markings or measurements will be readily apparent. For work which must be extremely accurate, feeler gauges of any suitable type may be inserted at spaced points between the knife edge 10 or 10 and the contiguous face of the work piece to determine the accuracy of the work piece to a fine degree.

The cylindrical form of the base has an additional advantage, particularly when the square is used on the bed plate of a milling machine or the like, the top face 'of which usually has longitudinally extended slots or ways therein, 'since the base has no side corners which can catch or snag in these ways when the square is slid thereacross, thus facilitating use of the square on such bed plates.

The cylindrical form of the base also affords the blade a stability which is not attainable by bases of prior bench squares having the same or even greater weight, and blades of a considerable length may be firmly supported by such a cylindrical base. In addition, the radial flange 2 or 2 provides the base with a substantially greater bench plate-engaging area than the body of the base provides alone.

During use of the bench square, dirt, dust, oil deposits, or the like which may be on the bench'plate are cleaned therefrom by a number of beveled cleaning slots 21 which span the bottom face of the base, these slots 21 defining pockets or dirt-receiving grooves in which the dirt is collected, and such foreign matter is prevented from causing even minute misalignment of the square blade from a truly perpendicular relation to the bench plate.

While the invention has been herein described in detail, it is not confined to such specific details alone, since changes and alterations may be resorted to without departing from the spirit thereof as defined in the appended claims.

I claim:

1. A bench square of the class described, comprising a base of substantial mass having a bottom face for supporting the base in an upright position on a flat surface, a blade detachably carried by said base and having a work piece-engaging edge, said base having a longitudinally extended groove in one side thereof, and said blade having a portion seated in said groove, said blade also having a stop projection intermediate its ends, said stop projection being engageable with the upper end of said base, and fastening means extended horizontally in said base and engageable with said blade for removably securing said blade in the groove in the base.

2. A bench square of the class described, comprising a cylindrical base having a longitudinally extended radial groove in one side thereof, a longitudinally extended blade having a portion complemental to and snugly receivable in said groove, said base having a plurality of radially extended apertures therein opening into said groove, said blade having a plurality of transversely extended recesses therein, cooperative abutment means on the base and on the blade for locating said blade relative to said base with the said apertures in axial alignment with said recessesv in the blade, said blade having one end projecting from one end of the base and having its other end terminating in the' groove in said base, and fastener means disposed in said apertures and projecting into said recesses for securing said blade in the groove in said base.

3. A bench square as defined in claim 2, wherein said base is provided with a radially projecting flange at the bottom thereof.

4. A bench square of the class described, comprising a cylindrical base having parallel'top'and bottom faces, a flange at the bottom of said base and having a circular outer margin, said base having a groove in one of its sides extending longitudinally from the top to the bottom there of, a longitudinally extended member seated in said groove and having a shoulder overlying and abutting the top face of the base, fastening means radially disposed in said base and extending into said groove to secure the member in place, and said member having means for anchoring engagement with said fastening means.

5. A bench square of the class described, comprising a base having parallel top and bottom faces, a flange at thebottom of said base and having a circular outer margin, said base having a groove in one of its sides extending longitudinally from the top to the bottom thereof, a blade seated in said groove and having a shoulder intermediate its ends, said shoulder overlying and abutting the top face of the base, the extreme bottom end of said blade terminating ,above the extreme bottom end of the groove, fastening means radially disposed in said base and extending into said groove to secure the blade in place, and said blade having means for anchoring engagement with said fastening means.

References Cited in the file of this patent UNITED STATES PATENTS 2,326,562 Rensen Aug; 10, 1943 2,474,577 Gwcer June 28, 1949 2,594,844 Bauerle Apr. 29, 1952 FOREIGN PATENTS v 111,601 Great Britain Dec. 6, 1917 120,171 Great Britain Oct. 31, 1918 414,630 Germany June 8, 1925' 110,302 Sweden Feb. 10, 1944 249,156 Switzerland Mar. 16, 1948 621,482 Great Britain Apr. 11, 1949 OTHER REFERENCES PubLLTaft-Peirce Handbook, pub. 1940, page 103.

(Copy in Div. 66.) 

